import 'package:flutter/material.dart';


import 'ExpandedComp2.dart';

//    
//  flutter run
void main() {
  
  runApp(
    MaterialApp(
    home: Scaffold(
      // 1.1 导航

      // 1.2 主体部分
  body: const CustomScrollViewWidget(),

    ),
  )
  




  
  );
   
 }




class MyApp extends StatelessWidget {
  // 构造函数，使用 super.key 将 key 传递给父类
  // key 是 Widget 的唯一标识符，用于在 Widget 树中识别和更新 Widget
  const MyApp({super.key});

  // 重写 StatelessWidget 的 build 方法
  // build 方法用于描述 Widget 的 UI 结构
  @override
  Widget build(BuildContext context) {
    // 返回一个 Center Widget，用于将其子 Widget 居中显示
    return const Center(
      // Center 的子 Widget 是一个 Text Widget，用于显示文本
      child: Text(
        // 显示的文本内容
        '坤坤',
        // 设置文本的阅读方向为从左到右（Left-to-Right）
        textDirection: TextDirection.ltr,
        // 设置文本的样式
        style: TextStyle(
            // 设置字体大小为 30
            fontSize: 30.0,
            // 设置文本颜色为红色
            color: Colors.red,
            // 设置字体加粗
            fontWeight: FontWeight.bold),
      ),
    );
  }

}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title});

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  void _incrementCounter() {
    setState(() {
      // This call to setState tells the Flutter framework that something has
      // changed in this State, which causes it to rerun the build method below
      // so that the display can reflect the updated values. If we changed
      // _counter without calling setState(), then the build method would not be
      // called again, and so nothing would appear to happen.
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {
    // This method is rerun every time setState is called, for instance as done
    // by the _incrementCounter method above.
    //
    // The Flutter framework has been optimized to make rerunning build methods
    // fast, so that you can just rebuild anything that needs updating rather
    // than having to individually change instances of widgets.
    return Scaffold(
      appBar: AppBar(
        // TRY THIS: Try changing the color here to a specific color (to
        // Colors.amber, perhaps?) and trigger a hot reload to see the AppBar
        // change color while the other colors stay the same.
        backgroundColor: Theme.of(context).colorScheme.inversePrimary,
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: Text(widget.title),
      ),
      body: Center(
        // Center is a layout widget. It takes a single child and positions it
        // in the middle of the parent.
        child: Column(
          // Column is also a layout widget. It takes a list of children and
          // arranges them vertically. By default, it sizes itself to fit its
          // children horizontally, and tries to be as tall as its parent.
          //
          // Column has various properties to control how it sizes itself and
          // how it positions its children. Here we use mainAxisAlignment to
          // center the children vertically; the main axis here is the vertical
          // axis because Columns are vertical (the cross axis would be
          // horizontal).
          //
          // TRY THIS: Invoke "debug painting" (choose the "Toggle Debug Paint"
          // action in the IDE, or press "p" in the console), to see the
          // wireframe for each widget.
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            const Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.headlineMedium,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: const Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}
